I got the data for a single screen_name and now I would like to pull the tweets for multiple screen_names at once through Curl.
I have tried this using POST but it didn’t work. I have been trying this since 7 days.

Getting timelines for multiple users will involve multiple calls to statuses/user_timeline.json, changing the screen_name parameter for each user - how you implement that depends on what library and language you end up using. The library should take care of all the OAuth and request stuff.